Multi-person shared display device

ABSTRACT

The object of the present invention is to provide a multi-person shared display device with which a display device can be shared by a plurality of persons. For this purpose, a display device of the present invention is configured by a large screen display  112  and a display mask  114 , which covers and hides a portion thereof. The display mask  114  is disposed at a position only an appropriate distance away from a display surface  116 . The display mask  114  has a hole  118 , and only through that portion can the display surface  116  of display  112  be seen. By introducing such display mask  114 , the region visible upon the display surface differs depending on the viewpoint position of the user. As a result, it becomes possible to provide different content for every user.

TECHNOLOGICAL FIELD

The present invention relates to a display device. In particular, it isrelated to display device allowing a plurality of users to share acommon display device.

BACKGROUND TECHNOLOGY

In recent years, computers and the environment surrounding computers hasbeen rapidly expanding. Together with such expansion, technology usingcomputers is widely used and has become commonplace so that these dayscomputers can be seen in every aspect of our daily lives.

Within this expansion of the environment surrounding computers,technology related to virtual reality is also expanding. The increasingspeed of computers has made it possible to bring the construction ofcomplicated virtual environments to even greater heights. Currently,this virtual reality technology has come to be used in various fields,and objects realized in virtual worlds are wide-ranging from large scaleto small scale and high definition, such as outer space, metropolitanareas, environments in nature, manufactured products, internal organs,small animals, cells, and atoms. Moreover, not only is it being used forthat which actually exists and can be actually seen, but also it isbeing used to visualize temperature distribution, airflow, andelectromagnetic fields, which cannot actually be seen.

Amazing expansion has been attained in three-dimensional image displaytechnology used to achieve such virtual reality, and utilization thereofranging from installations at expositions or use for amusement purposes,to applications in the fields of education and medicine and applicationsin the various design, CAD/CAM, and measurement fields deserves ourattention.

Techniques of displaying three-dimensional images are generallyclassified into a technique where a stereoscopic image is formed usingan appropriate method and having the viewer of such image view itwithout assistance, and a binocular disparity technique devised so that,instead of a stereoscopic image, a right-eye view and a left-eye view ofa flat image is formed and the right-eye view is viewed by the right eyeand the left-eye view is viewed by the left eye. Typical examples of theformer include holography and integral photography, and the latterincludes three-dimensional movies where polarized glasses or liquidcrystal shutters are used, and three-dimensional television usinglenticular film.

These techniques of forming three-dimensional images, as typified byholography, still have unresolved technical issues preventing fullcolor, high resolution, and real time viewing.

The binocular disparity technique is based on ergonomics, and providesthree-dimensional images giving an enhanced ‘real’ feeling, and superiorimmersion and sensory feelings. However, it is not possible to freelychange the viewpoint from which the three-dimensional object shown isviewed to coordinate with the user's movements using this technique byitself.

A method which modifies the three-dimensional image in accordance withthe viewpoint and position of the viewer, a device (e.g., magneticsensors or the like) worn for measuring the position of the head(viewpoint) of the viewer plus the binocular disparity technique allowsthe three-dimensional image to be viewed relative to the viewpointposition. However, with this technique, the number of users for whichviewpoint movement within real-space can be reflected in the virtualworld is limited to one person for each display. There is no displaymethod appropriate for a plurality of viewpoints when a plurality ofusers shares a common display.

There are methods of performing time divided display for the number ofusers (for example, refer to MIYASATO, Tsutomu, et al., GeneralConference of the Institute of Electronics Information and CommunicationEngineers, A 16-21, 1997, or Japanese Patent Application Laid-open Hei10-260377) and methods of driving display devices corresponding to thenumber of users in response to viewpoint position (for example, refer toKIMURA, Katsuyuki, et al., Conference on Three-Dimensional Imaging, 5-7,1994). However, with the former, as the number of viewers increases, theallowable lower frequency limit of the composition of thethree-dimensional view is not reached (the number of frames decreases),the display frequency is in inverse proportion to the number of users,which cause problems such as flickers to occur. With the latter, thenumber of display devices matching the number of users or a large-scaledevice is required, which is problematic in terms of price.

Thus, conventional devices for three-dimensional display of images andvideo have primarily come to use methods which display video for theright eye and video for the left eye using time division, and viewing isperformed by putting on special glasses which open/close windows for theright and left eyes synchronous with the timing of this switching. Inthis case, the viewer is able to view the video via a screen from anyposition without distortion caused by that viewpoint positioning.

However, if a plurality of people try to view the same three-dimensionalvideo without distortion, since the display switches back and forthbetween the right eye and left eye video of a plurality of positions,the time interval between displaying an image for each person that hasincreased the number of time divisions becomes longer, causing a flickerto be sensed.

DISCLOSURE OF INVENTION

An object of the present invention is to provide a multi-person shareddisplay device capable of displaying in response to viewpoint movementin real space. Another object of the present invention is to provide amulti-person shared display device capable of displaying a threedimensional image.

In order to achieve the above-mentioned objects, the present inventionis a multi-person shared display device, in which a display device isshared by a plurality of users; it is characterized by comprising: adisplay device, which displays a plurality of video for a plurality ofusers on a screen; a display mask, which is disposed so as to cover saiddisplay device separated by a fixed distance and has a sufficientlylarge hole; a position sensor, which detects a location of a user inreal space corresponding to said display device; and a processingdevice, which is dynamically combined with said one display device andsaid position sensor, and displays an image corresponding to each userupon said display device in accordance with the position of the userthrough said position sensor.

The proposed multi-person shared display device uses a display mask inwhich a hole is formed and covers the display device so as to hideportions besides the hole, allowing different display regions upon thedisplay device to be set in accordance with the viewpoint positionwithin real space of each user. This makes it possible to performdisplay in response to viewpoint movements of a plurality of users.

Video to be displayed upon a display device can include video forthree-dimensional viewing.

In this case, each user wears a plurality of glasses for separating saidvideo for three-dimensional viewing displayed into that for the righteye and that for the left eye, and the plurality of video for threedimensional viewing shown on said display device, are images allowingseparation between that for the right eye and that for the left eyethrough said plurality of glasses.

Also, glasses in which shutters for the right eye and for the left eyeopen and close can be used as said glasses; and said processing devicecan be dynamically combined with said glasses.

By forming said glasses and said position sensor as an integral unit,the position of a user can be found with little error.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram showing a configuration of an embodiment of thepresent invention.

FIG. 2 is a diagram showing an example of a display according to anembodiment of the present invention.

FIG. 3 is a diagram showing an example of an image produced by thisembodiment.

FIG. 4 is a diagram showing an example of coordinates in the case whereviewpoint is calculated.

FIG. 5 is a diagram showing the relationship between the display surfaceand a virtual object.

FIG. 6 is a diagram showing how a coordinate axis is determined.

FIG. 7 is a diagram showing display area for the viewpoint of a user.

FIG. 8 is a diagram showing an embodiment of a theatre display device.

FIG. 9 is a diagram showing a configuration applied to entertainmentpurposes.

FIG. 10 is a diagram showing an example where information is displayed.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention are described forthwith whilereferencing the drawings.

To begin with, an example where a three-dimensional image is shown witha multi-person shared three-dimensional display device is described.

FIG. 1(a) is a diagram showing a configuration of a multi-person sharedthree-dimensional display device according to an embodiment of thepresent invention. In FIG. 1(a), two users 140 and 150 of a multi-personshared three-dimensional display device each have on liquid crystalshutter glasses 142, 152, respectively, and also have a respectiveposition sensor 144, 154 attached. The users view an image displayedupon a display screen 110 via the liquid crystal shutters. The liquidcrystal shutter glasses 142, 152, position sensors 144, 154, and displaydevice 110 are connected to a processing device 130. In conformity withthe input from the position sensors, the processing apparatus 130displays an image upon the display at a region corresponding to eachrespective user.

The display device 110, as shown in FIG. 1(b), is configured from adisplay 112 and a display mask 114, which covers and hides a portionthereof. The display mask 114 is set at a position separated only anappropriate distance away from a display surface 116. A hole 118 isformed in the display mask 114, and through only that portion can thesurface 116 of the display 112 be seen.

By introducing such a display mask 114, as shown in FIG. 2, the viewableregion upon the display surface varies depending on the viewpointposition of the user. As a result, it becomes possible to vary thecontents exhibited to each user. In addition, with this configuration,it becomes possible to coordinate with the interactive viewpointmovement of a user. In the case where the viewpoint position of a usermoves, the region viewable by the user also changes depending on thatmovement. Accordingly, by detecting viewpoint position using theposition sensor and displaying at a region befitting that viewpointposition, it is possible to adapt to the movement of the viewpointposition of the user.

Moreover, with a system using this technique, by presenting an imagehaving disparity between the respective right and left viewpoint forevery display region and for every viewpoint position, it becomespossible to perform three-dimensional display for all viewers. As aresult, a multi-person shared three-dimensional virtual space can berealized as three-dimensional display is being performed for all viewersin the same virtual space.

For example, a magnetic sensor having 6 degrees of freedom can be usedas the viewpoint position detection sensor. The magnetic sensor candetect the current position by detecting magnetic flux cutoff in everyrespective direction x, y, and z. Assuming that the direction of theline of sight faces the center of the hole upon the mask and that a lineconnecting both eyes parallels the horizontal surface, that direction ofthe line of sight can be calculated in real time from the viewpointposition detected.

Besides the magnetic sensor utilizing a magnetic field as describedabove, it is also possible to use any well known sensor utilizing anelectric field, an electromagnetic field, ultrasonic waves, or the like,as the position detection sensor. In addition, the position detectionsensor may be constructed integrated in the liquid crystal shutterglasses.

The processing device 130 is provided comprising projecting an image forthe respective right and left viewpoint derived and time-divided,alternating displaying upon a display 112 synchronous to the liquidcrystal shutters. Actually, as shown in FIGS. 3(a) and (b), outputtingimages corresponding to the respective right and left viewpoints to therespective upper and lower half of the entire screen and switchingbetween the respective top and bottom half thereof, this system displaysenlargement thereof. This allows, for example, a display frequency of120 Hz to be divided into 60 Hz to show the right and left images. Theliquid crystal shutters switch between both right and left, viewable andnon-viewable, by synchronizing with the image refresh rate. The factthat the display 112 is viewed through the liquid crystal shutterglasses makes it possible to obtain images that correspond to therespective right and left viewpoints, thereby allowing three-dimensionalviewing.

In the above description, the top and lower halves are output one at atime; however, in what manner division and display are carried out, orwhether display is carried out without division, or if display isaccomplished through interlacing or so forth, can be freely set.Further, besides a display device that provides a normal light-emittingsurface to be directly viewed, a projector type display device may alsobe used.

<Viewpoint Position>

Next, using FIG. 4, how the position of both the left and right eye iscalculated so as to perform three-dimensional display is described;where that position is derived, assuming the viewpoint position obtainedusing the positional sensor to be equal to the center of the eyes, basedon the direction of the line of sight and the attitude angle derivedfrom calculations. As shown in FIG. 4, the center position of the user'seyes and the distance from the center to both of the respective eyes,the rotational angle of the light of sight from the straight forwarddirection, along with the position of both respective eyes are definedas the following:

(x_(eye), y_(eye), z_(eye)) center position between both eyes (1)d_(eye) distance to both respective right and left eyes θ rotationalangle of the line of sight from the straight forward direction(x_(l-eye), y_(l-eye), z_(l-eye)) position of left eye (x_(r-eye),y_(r-eye), z_(r-eye)) position of right eye

When defined as in (1) above, the right and left viewpoint positions canbe derived as the following equations (2):

 x _(l-eye) =x _(eye) −d _(eye) cos θy _(l-eye) =y _(eye) −d _(eye) sin θz_(l-eye)=z_(eye)x _(r-eye) =x _(eye) −d _(eye) cos θy _(r-eye) =y _(eye) −d _(eye) sin θz_(r-eye)=z_(eye)

In this case, if the positional sensor is constructed integrated withglasses incorporating liquid crystal shutters, error is especiallysmall, and it is possible to calculate the viewpoint position from thepositional information obtained by the positional sensor, as describedabove.

<Setting of Projection Surface>

When movement of the viewpoint position is considered, it becomesnecessary to set the position of the projection surface so that it iscapable of handling the positional relationship of the viewpoint and thedisplay surface. The method where the projection surface and the displaysurface are made to match can be used as a most basic method ofappropriately setting the projection surface. With this method, in thecase where the absolute position of the display surface within the realworld is invariant, the absolute position of the projection surfacewithin the virtual world is also invariant, there is no need to considercorrection of the absolute position of the projection surface, and itbecomes acceptable to consider only the relative position from theviewpoint.

In addition, when the position of a virtual object assumed to exist lieson the other side of the viewpoint relative to the display surface inreal space, in other words, in the case where the display surface isthought of as a window and one is peering into the virtual world throughthe window, the projection surface should be set to match the displaysurface in the simplistic manner described next.

However, generally, in the system for rendering the virtual world, sincethe virtual world in front of the projection surface relative to theviewpoint is impossible to render, in cases where a virtual objectexists on the side in front of the display surface relative to the user,it is not appropriate to set the projection surface to match the displaysurface.

Therefore, with the system of this embodiment, as shown in FIG. 5(a),assuming the rectangular area, which has four apexes that match eachrespective intersection of the four straight lines connecting eachrespective four nodes of a display surface 116 to the viewpoint and aplane at the rear of which the virtual object 520 exists parallel to thedisplay surface 116 to be a projection surface 510, the projected imageis enlarged and displayed upon the display surface 116 providingappropriate presentation of an image. It is noted that in the case wheresuch a method is used, since the absolute position itself of theprojection surface 510 changes, it is necessary to derive the absoluteposition of the projection surface 510 for every change in viewpointposition.

FIG. 5(b) shows an example of a display screen in the case where arelationship among the projection surface, the display surface, and thevirtual object such as that shown in FIG. 5(a) is assumed. If arelationship such as that shown in FIG. 5(a) is assumed, that which isto be shown upon the display surface 116 in the real world is anenlarged image.

In this manner, with the system of this embodiment, it is possible tofreely set the relationship between the display surface and theprojection surface. This makes it possible to display a virtual objectby setting the projection surface without being limited to the actualdisplay surface.

<Derivation of Display Region and Display>

A display region corresponding to the viewpoint position of the user isderived and image rendering is performed in that region. On thisoccasion, when the hole 118 upon display mask 114 is circular, thedisplay region corresponding to the position of the user viewpoint isalso circular, and the position of the center thereof is determined inconformity with the following two parameters.

-   -   Position of the viewpoint upon the display coordinate system    -   Distance between the mask and the display surface        It is noted that with the system of this embodiment, the        distance between the mask 114 and the display surface 116 is        fixed.

The center of the display surface 116 is made the origin, the coordinatesystem having the center of display surface 116 as the origin is set asshown in FIG. 6, with the viewpoint upon that coordinate system, thedistance between the mask and the display surface, and the position ofthe center of the display region being defined as the following:

(x_(eye), y_(eye), z_(eye)) viewpoint position d_(mask-display) distancebetween mask and display surface (x_(center), y_(center), z_(center))center position of display region

Based on the above-mentioned definitions, as shown in FIG. 7(a), thecenter position of a display region 242 is derived from the followingrelational expression: $\begin{matrix}{{x_{center} = {{- x_{eye}} \times \frac{d_{{mask} - {display}}}{z_{eye} - d_{{mask} - {display}}}}}{y_{center} = {{- y_{eye}} \times \frac{d_{{mask} - {display}}}{z_{eye} - d_{{mask} - {display}}}}}{z_{center} = 0}} & (3)\end{matrix}$

In addition, as shown in FIG. 7(b) the radius defining the magnitude ofthe circular display region 242, is derived from the following threeparameters:

-   -   distance of the viewpoint from the display surface    -   distance between the mask and the display surface    -   radius of the hole upon the mask        Here the radius of the hole 118 upon the mask 114 and the radius        of the display region 242 are respectively defined as the        following:

r_(hole) radius of the hole on the mask r_(draw) radius of the displayregionIn this case, the radius r_(draw) of the display region is representedby the following:$r_{draw} = {r_{hole} \times \frac{z_{eye}}{z_{eye} - d_{{mask} - {display}}}}$

By performing processing of the display region in the above manner, itis possible to perform display of an image for every user in the displayregion 242 that is dynamically derived in accordance with the positionof the respective user.

<Detection of Overlapping Display Regions>

Since there is a plurality of users, it is necessary to perform anoverlapping search among regions derived in conformity with theprocessing described above. In the case where the display region iscircular, detection of an overlapping region can be performed throughthe relationship of the distance between centers and the sum of theradiuses. With a system of this embodiment, when overlapping isdetected, the users can be alerted to an overlapping display regionthrough, for example, the rendering of a demarcation line for thedisplay region.

With the system of this embodiment, for example, the display has arectangular shape with a width of 1360 mm and height of 1020 mm, andfrom the surface of the floor the height of the display surface is 1000mm. The distance between the display mask and the display surface is 150mm and the radius of the mask hole is 200 mm.

<Other Embodiments>

The system of the embodiment described above is an example where thedisplay surface is placed horizontally; alternatively, the displaysurface may naturally be placed vertically or at a slant. If the displayis made to be the projection type, it is possible to achieve a largescreen display. In addition, in order to configure a large display, aplurality of displays may be combined.

FIG. 8 shows a theatre-style multi-person shared three-dimensionaldisplay device capable of being used by multiple persons. With thetheatre style multi-person shared three-dimensional display device, forexample, given a width of 25 m, height of 18 m, distance of 6 m betweenthe display mask and the display surface, radius of 0.5 m for the maskhole of the display mask, a maximum of forty-eight persons cansimultaneously view the respective videos.

It is not necessary to make the hole upon the display mask circular; forexample, a rectangular shape is also allowable.

If the display mask is configured with liquid crystal, it is possible tocontrol the radius, shape, and location of the hole of the display maskthrough the permeability and non-permeability of the liquid crystal.

In addition, in order to control the radius, etc. of the hole of thedisplay mask, for example, a mechanical mechanism such as an aperturemechanism or the like can be used.

With the multi-person shared three-dimensional display apparatusdescribed above, glasses with attached shutters are utilized wherein theopening and closing of the shutters is synchronized and imagescorresponding to the left/right line of sight are displayed to obtain athree-dimensional image; however, the present invention is not limitedto this method for obtaining a three-dimensional view. For example, afilter based on polarization or color may be used as the glasses to beworn to segregate images corresponding to the left and right lines ofsight.

In addition, as an example of three-dimensional display not usingglasses, there is the display device mentioned in, for example, JapanesePatent Application Laid-open No. 2001-13457.

It is possible to use these multi-person shared three-dimensionaldisplay devices, for example, for entertainment purposes. Aconfiguration example corresponding to such entertainment purposes isshown in FIG. 9. In FIG. 9(a), audience members traveling aboard carts421, 422, and 423, respectively, view a display 416 via a hole 418 indisplay mask 414. FIG. 9(b) shows a configuration where athree-dimensional image displayed on a display 516 is viewed through ahole 518 in a display mask 514 while a plurality of audience members aremoving about a central stage.

When the fact that display on a display surface is possible byseparating images for every person with a display hole is utilized, notonly images for three-dimensional viewing, but also display of differentinformation for each person is possible. An example of thisconfiguration is shown in FIG. 10. This configuration, as shown in FIG.10, is a fundamentally similar configuration as the multi-person sharedthree-dimensional display device shown in FIG. 1. With thisconfiguration, sensors 162, 164, 166 are attached to each audiencemember and the respective position of each audience member is detectedthrough a processing device 130. The processing device 130, inconformity with the detected positions, performs display correspondingto each person on the display regions 224, 226, 228 respectivelyassociated with each audience member.

With the multi-person shared display device of the present invention, itis possible to perform appropriate display corresponding to viewpointmovement for a plurality of persons.

With this multi-person shared display device, the relative positionsbetween the viewpoint and projection surface in the virtual world areappropriately corrected corresponding to changes in the relativepositions between the viewpoint and projection surface in the realworld. Moreover, with the present invention, for example with a singlefixed display, a three-dimensional image can be displayed for aplurality of moving users having neither flickering nor spatialdistortion. In addition, regions of viewpoint movement allowing a userto obtain an appropriate image have also been described in detail.

The present invention is applicable to not only a stand-alone computersystem, but may also be made applicable to, for example, a client serversystem or the like configured from a plurality of systems.

It is possible to provide a configuration of the present invention byhaving a system read out a program relating to the present inventionfrom storage media stored with the program and execute it. Such storagemedia includes floppy disks, CD-ROMS, magnetic tape, and ROM cassettes.

INDUSTRIAL APPLICABILITY

With the display device of the present invention, an image rendered upona screen in compliance with the individual audience member positions isviewed via a hole of an appropriate size an appropriate distance fromthe screen. As a result, it is possible to view video in compliance withthe individual viewpoint positions of a plurality of persons.

Technology relating to such a multi-person shared display device iscapable of wide range industrial applicability, for example as a devicefor viewing three-dimensional objects.

1. A multi-person shared display device, which is a display deviceshared by a plurality of users, comprising: a display device, whichdisplays a plurality of images for a plurality of users on a screen; adisplay mask, which is disposed so as to cover said display deviceseparated by a fixed distance and has one fixed sufficiently large holethrough which each of said plurality of users watches said imagecorresponding to the user on said display device, and by which a visibleregion upon the display surface varies depending on viewpoint positionof each of the users; a position sensor, which detects a location of theuser in real space corresponding to said display device; and aprocessing device, which is dynamically combined with said displaydevice and said position sensor, and varies an image upon said displaydevice in accordance with said location of the user through saidposition sensor so that relative positions between viewpoint and saiddisplay device are appropriately corrected corresponding to changes inthe relative positions.
 2. The multi-person shared display deviceaccording to claim 1, wherein said image to be displayed upon thedisplay device includes video for three-dimensional viewing.
 3. Themulti-person shared display device according to claim 2, wherein eachuser wears a plurality of glasses for separating said video forthree-dimensional viewing displayed into that for the right eye and thatfor the left eye; and the plurality of video for three dimensionalviewing shown on said display device, is images allowing separationbetween that for the right eye and that for the left eye through saidplurality of glasses.
 4. The multi-person shared display deviceaccording to claim 3, wherein said glasses are glasses in which shuttersfor the right eye and for the left eye open and close; and saidprocessing device is dynamically combined with said glasses.
 5. Themulti-person shared display device according to either claim 3 or claim4, wherein said glasses and said position sensor are formed as anintegral unit.
 6. The multi-person shared display device according toclaim 1, further including a shutter for right eye and for left eye openand close wherein said processing device is dynamically combined withsaid shutter.
 7. A multi-person shared display device, which is adisplay device shared by a plurality of users, comprising: a displaydevice, which displays a plurality of video for a plurality of users ona screen, wherein said video to be displayed upon the display deviceincludes video for three-dimensional viewing; a display mask, which isdisposed so as to cover said display device separated by a fixeddistance and has a sufficiently large hole; a position sensor, whichdetects a location of a user in real space corresponding to said displaydevice; and a processing device, which is dynamically combined with saidone display device and said position sensor, and displays an imagecorresponding to each user upon said display device in accordance withsaid position of the user through said position sensor wherein each userwears a plurality of glasses for separating said video forthree-dimensional viewing displayed into that for the right eye and thatfor the left eye; the plurality of video for three dimensional viewingshown on said display device, is images allowing separation between thatfor the right eye and that for the left eye through said plurality ofglasses; said glasses are glasses in which shutters for the right eyeand for the left eye open and close; and said processing device isdynamically combined with said glasses.
 8. The multi-person shareddisplay device according to claim 7, wherein said glasses and saidposition sensor are formed as an integral unit.